JBL SUB 550P / 230 Amplifier/Subwoofer –
Controls & connections – SMPS & Amplifier Schematic (Circuit diagram)
SUBWOOFER REAR-PANEL CONTROLS AND CONNECTIONS
Phase switch: This switch
determines whether the subwoofer driver’s piston-like action moves in and out
in phase with the system’s other speakers. If the subwoofer were to play out of
phase with the other speakers, the sound waves from the other speakers could
partially cancel out the sound waves from the subwoofer, reducing bass
performance and sonic impact. This phenomenon depends in part on the placement
of all the speakers relative to each other in the room.
Input Mode switch: When this
switch is in the “Normal” setting, the input signal from the Line In connectors
is active. When this switch is in the “LFE” setting, the input signal from the
LFE In connector is active, and the subwoofer’s internal crossover is bypassed.
Level control: Use this control to adjust the subwoofer’s volume. Turn the knob clockwise to increase the volume; turn the knob counterclockwise to decrease the volume.
Crossover control: This control determines the highest frequency at which the subwoofer reproduces sounds. The higher you set the Crossover control, the higher in frequency the subwoofer will operate and
the more its bass will “overlap” that of the system’s other speakers. This adjustment helps achieve a smooth transition of bass frequencies between the subwoofer and the other speakers for a variety of different rooms and subwoofer locations. NOTE: The Crossover control functions only when the Input Mode switch is in the “Normal” position. When the switch is in the “LFE” position the subwoofer’s built-in crossover and Crossover control are bypassed.
On/Standby indicator: This LED indicates whether the subwoofer is in the On or Standby state:
* When the LED glows green, the subwoofer is turned on.
* When the LED glows red, the subwoofer is in the Standby mode.
* When the LED is off, the subwoofer’s Power switch is set to “Off.”
Level control: Use this control to adjust the subwoofer’s volume. Turn the knob clockwise to increase the volume; turn the knob counterclockwise to decrease the volume.
Crossover control: This control determines the highest frequency at which the subwoofer reproduces sounds. The higher you set the Crossover control, the higher in frequency the subwoofer will operate and
the more its bass will “overlap” that of the system’s other speakers. This adjustment helps achieve a smooth transition of bass frequencies between the subwoofer and the other speakers for a variety of different rooms and subwoofer locations. NOTE: The Crossover control functions only when the Input Mode switch is in the “Normal” position. When the switch is in the “LFE” position the subwoofer’s built-in crossover and Crossover control are bypassed.
On/Standby indicator: This LED indicates whether the subwoofer is in the On or Standby state:
* When the LED glows green, the subwoofer is turned on.
* When the LED glows red, the subwoofer is in the Standby mode.
* When the LED is off, the subwoofer’s Power switch is set to “Off.”
SUB 550P BASIC SPECIFICATIONS
Low-frequency transducer: 10" (250mm) PolyPlas cone, cast
basket
Enclosure type: Sealed (forward-firing)
Amplifier power: 300 watts (RMS); 500 watts (peak)
Frequency response: 27Hz – 150Hz
Audio controls: Volume level, crossover frequency, phase
Connections: RCA line-level and LFE inputs
Power requirement: 120V, 60Hz (US); 220V – 230V, 50Hz/60Hz (EU)
Power consumption: <6W (120V) standby 360W (3.8A @ 120V)
maximum <0.55W (230V) standby 395W (2.1A @ 230V) maximum
Dimensions (W x H x D): 17-1/2" x 14-29/32" x
14-31/32" (444mm x 379mm x 380mm)
Weight: 50 lb (23kg)
PLACING THE SUBWOOFER
The performance of a subwoofer is directly related to its placement in the listening room and its physical position relative to the other speakers in the system.
While it is true that in general our ears do not hear directional sounds at the low frequencies where subwoofers operate, when installing a subwoofer within the limited confines of a room, the reflections, standing waves and absorptions generated within the room will strongly influence the performance of any subwoofer system. As a result, the specific location of the subwoofer in the room does become important to the amount and quality of bass that is produced.
For example, placing the subwoofer next to a wall generally will increase the amount of bass in the room; placing it in a corner (1) generally will maximize the amount of bass in the room. However, corner placement can also increase the destructive effect of standing waves on bass performance. This effect can vary depending on the listening position – some listening positions may yield very good results while others may have far too much (or too little) bass at certain frequencies. In many rooms, placing the subwoofer along the same plane as the left and right speakers (2) can produce the best integration between the sound of the subwoofer and that of the left and right speakers. In some rooms, the best performance could even result from placing the subwoofer behind the listening position (3).
Experiment with placement before choosing a final location for your subwoofer. One way you can determine the best location for the subwoofer is by temporarily placing it in the listening position and playing music with strong bass content. Move around to various locations in the room while the system is playing (putting your ears where the subwoofer would be placed), and listen until you find the location where the bass performance is best. Place the subwoofer in that location.
The performance of a subwoofer is directly related to its placement in the listening room and its physical position relative to the other speakers in the system.
While it is true that in general our ears do not hear directional sounds at the low frequencies where subwoofers operate, when installing a subwoofer within the limited confines of a room, the reflections, standing waves and absorptions generated within the room will strongly influence the performance of any subwoofer system. As a result, the specific location of the subwoofer in the room does become important to the amount and quality of bass that is produced.
For example, placing the subwoofer next to a wall generally will increase the amount of bass in the room; placing it in a corner (1) generally will maximize the amount of bass in the room. However, corner placement can also increase the destructive effect of standing waves on bass performance. This effect can vary depending on the listening position – some listening positions may yield very good results while others may have far too much (or too little) bass at certain frequencies. In many rooms, placing the subwoofer along the same plane as the left and right speakers (2) can produce the best integration between the sound of the subwoofer and that of the left and right speakers. In some rooms, the best performance could even result from placing the subwoofer behind the listening position (3).
Experiment with placement before choosing a final location for your subwoofer. One way you can determine the best location for the subwoofer is by temporarily placing it in the listening position and playing music with strong bass content. Move around to various locations in the room while the system is playing (putting your ears where the subwoofer would be placed), and listen until you find the location where the bass performance is best. Place the subwoofer in that location.
CONNECTING THE SUBWOOFER
TURNING THE SUBWOOFER ON AND OFF
Set the subwoofer’s Power Switch to the “On” position. The subwoofer will automatically turn itself on when it receives an audio signal, and it will go into Standby mode after it has received no audio signal for approximately 10 minutes. The subwoofer’s LED will glow green when the subwoofer is on and will glow red when the subwoofer is in Standby. If you will not be using the subwoofer for an extended period – for instance, if you’re going on vacation – set the Power Switch to the “Off” position.
SUBWOOFER ADJUSTMENTS: CROSSOVER CONTROL
NOTE: The Crossover control functions only when the Input Mode switch is in the “Normal” position.
The Crossover control adjusts the subwoofer’s built-in low-pass filter crossover between 50Hz and 200Hz. The higher you set the Crossover control, the higher in frequency the subwoofer will operate and the more its bass will “overlap” that of the satellite speakers. This adjustment helps achieve a smooth transition of bass frequencies between the subwoofer and the satellites for a variety of different rooms and subwoofer locations. To set the Crossover control, listen for the smoothness of the bass. If the bass seems too strong at certain frequencies, try a lower Crossover control setting. If the bass seems too weak at certain frequencies, try a higher Crossover control setting.
SUBWOOFER ADJUSTMENTS: VOLUME
Use the Level control to set the subwoofer’s volume. Turn the knob clockwise to increase the subwoofer’s volume; turn the knob counterclockwise to decrease the volume. Once you have balanced the subwoofer’s volume with that of the other speakers in your system, you shouldn’t have to change the Level control setting.
Notes on Setting Subwoofer Volume:
SOMETIMES THE IDEAL SUBWOOFER VOLUME SETTING FOR MUSIC IS TOO LOUD for films, while the ideal setting for films is too quiet for music. When setting the subwoofer volume, listen to both music and films with strong bass content and find a “middle ground” volume level that works for both.
IF YOUR SUBWOOFER ALWAYS SEEMS TOO LOUD OR TOO QUIET
Set the subwoofer’s Power Switch to the “On” position. The subwoofer will automatically turn itself on when it receives an audio signal, and it will go into Standby mode after it has received no audio signal for approximately 10 minutes. The subwoofer’s LED will glow green when the subwoofer is on and will glow red when the subwoofer is in Standby. If you will not be using the subwoofer for an extended period – for instance, if you’re going on vacation – set the Power Switch to the “Off” position.
SUBWOOFER ADJUSTMENTS: CROSSOVER CONTROL
NOTE: The Crossover control functions only when the Input Mode switch is in the “Normal” position.
The Crossover control adjusts the subwoofer’s built-in low-pass filter crossover between 50Hz and 200Hz. The higher you set the Crossover control, the higher in frequency the subwoofer will operate and the more its bass will “overlap” that of the satellite speakers. This adjustment helps achieve a smooth transition of bass frequencies between the subwoofer and the satellites for a variety of different rooms and subwoofer locations. To set the Crossover control, listen for the smoothness of the bass. If the bass seems too strong at certain frequencies, try a lower Crossover control setting. If the bass seems too weak at certain frequencies, try a higher Crossover control setting.
SUBWOOFER ADJUSTMENTS: VOLUME
Use the Level control to set the subwoofer’s volume. Turn the knob clockwise to increase the subwoofer’s volume; turn the knob counterclockwise to decrease the volume. Once you have balanced the subwoofer’s volume with that of the other speakers in your system, you shouldn’t have to change the Level control setting.
Notes on Setting Subwoofer Volume:
SOMETIMES THE IDEAL SUBWOOFER VOLUME SETTING FOR MUSIC IS TOO LOUD for films, while the ideal setting for films is too quiet for music. When setting the subwoofer volume, listen to both music and films with strong bass content and find a “middle ground” volume level that works for both.
IF YOUR SUBWOOFER ALWAYS SEEMS TOO LOUD OR TOO QUIET
YOU MAY WANT to place it in a different location. Placing the subwoofer in a corner will tend
to increase its bass output, while placing it away from any walls or corners
will tend to lessen its bass output.
SUBWOOFER ADJUSTMENTS: PHASE
The Phase switch determines whether the subwoofer driver’s piston-like action moves in and out in phase with the satellite speakers. If the subwoofer were to play out of phase with the satellite speakers, the sound waves from the satellites could partially cancel out the waves from the subwoofer, reducing bass performance and sonic impact. This phenomenon depends in part on the placement of all the speakers relative to each other in the room. Although in most cases you should leave the Phase switch in the “Normal” position, there is no absolutely correct setting for the Phase switch. When the subwoofer is properly in phase with the satellite speakers, the sound will be clearer and have maximum impact, and percussive sounds like drums, piano and plucked strings will sound more lifelike. The best way to set the Phase switch is to listen to music that you know well and to set the switch in the position that gives drums and other percussive sounds maximum impact.
The Phase switch determines whether the subwoofer driver’s piston-like action moves in and out in phase with the satellite speakers. If the subwoofer were to play out of phase with the satellite speakers, the sound waves from the satellites could partially cancel out the waves from the subwoofer, reducing bass performance and sonic impact. This phenomenon depends in part on the placement of all the speakers relative to each other in the room. Although in most cases you should leave the Phase switch in the “Normal” position, there is no absolutely correct setting for the Phase switch. When the subwoofer is properly in phase with the satellite speakers, the sound will be clearer and have maximum impact, and percussive sounds like drums, piano and plucked strings will sound more lifelike. The best way to set the Phase switch is to listen to music that you know well and to set the switch in the position that gives drums and other percussive sounds maximum impact.
SCHEMATICS
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